Means and method for welding silicon steel sheet stock



Oct. 10, 1939. r a. REED ET AL. 2,175,615

MEANS AND METHOD FOR WELDING SILICON STEEL SHEET STOCK Filed May 18, 1938 2 Sheets-Sheet 1 INVENTORS. 4W [0 P550 BY ffn/n fi M57254.

ATTORNEYS.

01111111939. E. REED ETAL. 2,175,615

MEANS AND METHOD FOR WELDING SILICON STEEL SHEET STOCK Filed May 18, 1938 2 Sheets-Sheet 2 Elm 6 L, I!!! IIIIIIIIIIIIIIIIIIIIII" [51. g Q

1 4 I 1E 32 g i 11111111- z-"l f i W z F v m L; .FIG.Z 4 V 35 Illlll ll llllilll INVENTORS 0 REED fig fi BY KARL F METZEL,

ATTORNEYS.

Patented Oct. 10, 1939 2,175,615

UNITED STATES PATENT OFFICE MEANS AND METHOD FOR WELDING SILI- CON STEEL SHEET STOCK Eo Reed and Karl F. Wietzcl. Zanesville, Ohio,

assignor to The American Rolling Mill Company, Middletown, Ohio, a corporation of Ohio Application May 18, 1938, Serial No. 208,641 2 Claims. (Cl. 113-59) Our invention relates to the formation of butt Figure 4 is a plan view of a welding machine. welds in silicon steel sheet stock for the forma- Figure 5 is a sectional view thereof taken lontion of strip of indefinite length therefrom. gitudinally along lines 5-5 of Fi u e Such strip is'useful in the manufacture of trans- Figure 6 is a traverse sectional view taken 5 former stampings and the like, for the continuo g i s -45 of u e ous feeding of punch presses, and for other puri r '7 is a perspective view of shee s being poses. Ordinarily, all of the silicon sheet steel welded end to end showing the relationship of stock handled and welded in this way would be the torches. considered light-gauge sheet metal. Owing to the extreme difficulty of welding 10 I t e co-pending application of Fay and Reed, thin silicon steel sheets, the sheets must not only (one of the inventors herein), Serial No. 132,824, be prepared for welding in a certain way but the filed March 24, 1937, there is described a method conditions of welding are specific in character. of welding thin silicon sheets, salient features of Thin silicon steel sheet stock is not characterized which are clamping the sheet ends under a cerby flatness. Thus when the silicon steel is tain pressure effective over a certain area and clamped, the y character s e ov d ver the shearing them. afterward butting the sheet edges clamped area After S e i a d t e re ease of and clamping them under the same pressure efthe clamping pressure, the wavy character of the fective over the same area so as to bring about sheet reappears and the cut edge is no longer precise coincidence, then welding the sheet edges r M r particularly if w h s. th end by a gas flame. Also in a co-pending applicaof which have been sheared under identical con- 20 tion of said Reed, Serial No. 212,039 filed June ditions are merely brought together in butted 6. 1938, there is set forth an apparatus suitable relationship, or clamped under differing pressures for the welding of thin silicon steel. In the over differing areas, the coincidence of their practice of our present process we use certain of butted edges will not usually be perfect enough the features of these processes. In commercial for welding. As a consequence, it is necessary 25 practice the processes referred to have given both to shear and weld the sheets while the edges excellent results in the welding of thin silicon thereof are clamped over identical areas by idensteel of widely varying silicon content in gauges tical pressures. up to 31; but as the gauges become heavier, then In Figure 1, I is a shear table having guide 8. the perfection of the results becomes less sure. A sheet 5, the edges of which are to be sheared, 30 i More particularly in gauges ranging around 24 is resting on the table. Ashear is indicated gena tendency has been noted for the weld to be imerally at l0 and is shown in more detail in Figperfect on the side opposite the torches though ures 2 and 3. Here ll represents the shear bed perfect on the torch side. When working with having a fixed. shear knife I2. A movable knife 35 metals of this fineness, and considering the limi- I3 is mounted on a suitable bridge H which is 85 tations of the general process, it is not feasible to slidable in ways on the shear frame. Motive cut the sheet edges aslant or beveled so as to let means for the shear bladeis, of course, provided. the flame get down into the space between the A magnetic hold-down or clamp is likewise prosheets. We have endeavored to arrange our vided consisting of a i e 5,00 8 members "i clamping means at the welding head in planes which are surrounded by c l and a D 40 which meet at an angle so as to get the effect of plate l8 which forms the clamping member. beveled sheet edges; but this has proved not to be This structure is made vertically slidable on rods so advantageous as the method herein disclosed. H on the frame of the shear, and is normally The general objects of our invention will be ur pw r ly y mp i n pr n 20. It apparent to one skilled in the art upon reading will be understood that when the coils H are 45 these specifications or will be pointed out hereenergized by electric current, the clamping means inafter; in these specifications, we accomplish will exerts. fixed pressure on the sheet 9 over our objects by that certain series of process steps the area of the pole plate 8 where it contacts and by that apparatus of which we shall now dethe sheet. Sheets are placed on the table 1 scribe an exemplary embodiment, reference is against the guide 8 and their ends are sheared in 50 made to the drawings wherein: succession, the sheets being reversed as will be Figure 1 is a semi-diagrammatic plan view of understood so as to shear each end.

an assembly for making coils of silicon steel strip. Referring again to Figure 1, a table for the Figure 2 is a vertical view of a shear. welding means is shown at 2|. This table has 56 Figure 3 is an elevation thereof. I a guide 22. The welding means comprises a pair of clamping means, one clamping means for the trailing end of the strip which has already been formed, and one clamping means for the leading end of the sheet or strip which is to be attached thereto. A cross section through the clamping means is to be found in Figure 6. Each clamping means comprises a member 23 having a pole piece 24, a second pole piece and intermediate core members 26, carrying coils I. So as to form a table for the ends of the sheet and strip respectively, we prefer to fill in the space between the pole piece 24 and the pole piece 25 with a non-magnetic metal 28, forming therein a passageway 29 for a cooling fluid. Above the mechanism just described, we provide a cooperating clamping plate 30. This plate, in the area thereof which contacts the sheet or strip respectively, has the same area as the clamping plate ii of the shear. The coils 21 are so arranged that when they are energized by the proper current, the same clamping pressure will be had at the welding head as was produced at the shear clamp. The clamping plates 30 may be mounted, by means of rods 3|, in brackets 32 on the structure and may be urged upwardly by compression springs 33. We form a passageway 34 for cooling fluid adjacent the inner edges of the clamping plates 30 as shown in Figure 6. This passageway may be formed as a slot or milling cut in the clamping plate, the upper end of which is closed by an elongated metallic plug 35.

The sheet edges have been cut square by the shearing operation described, and the sheets are clamped in butted position as shown in Figure 6. We employ in the welding pairs of torches of which we have shown a single pair in our drawings. There is an upper torch 36 and a lower torch 31; and the inner edges of the clamping plates 30 are beveled as shown so that these edges may be closely approached to the line of weld and still leave room for the passage of the upper torch 35. Similarly, the pole plates 25 below the line of weld are shaped so as to accommodate the lower torch 31.

In welding, we use a neutral gas flame. The me of a flame both above and below the line of weld causes the weld to be formed from both sides simultaneously so that a perfect weld can be secured within the permissible length of time of treatment of the thin silicon steel metals. The silicon steel is thus heated much more rapidly and is heated transversely across the butted areas of the sheets. It is necessary in this type of welding both to develop a welding heat at the butted edges and to protect the line of weld from an oxidizing atmosphere so long as the metal is at high temperature. Using a neutral flame on both sides of the line of weld makes it unnecessary to adopt any specific additional means for the protection of the metal from an oxidizing atmosphere. Steel containing large quantities of silicon is difficult to weld due to the preferential oxidation of the silicon therein into refractory silicon dioxide. In our apparatus, it will be noted that the magnetic clamping means approach the line of weld closely on both sides of the butted joint; and that the clamping means are water cooled so as to abstract heat rapidly from the sheet edges, whereby to cool the sheet edges rapidly well below the oxidation temperature elsewhere than at the area upon which the flames impinge. Also it will be noted that the flames are well pocketed at the line of weld.

By following our process, welding can be done 7 quite rapidly; and for this purpose, we provide mechanical means for moving the welding torches; In Figures 4 and 5, we have shown a machine comprising frame members 33 and 39 connected by a bridge portion 40. The clamping means hereinabove described is mounted on the bridge near one end thereof. The bridge comprises two interspaced portions which are machined to form ways. A carriage member 4| is slidably mounted on these ways. The carriage member bears a pair of arms 42 and 43 on which the torches 36 and 31 are respectively mounted in an adjustable manner. The showing of Figures 4 and 5 is semi-diagrammatic in character and it will be within the skill of the worker in the art to provide such adjustment features for the torches in connection with the arms and/or carriage as may be desired. The carriage may be moved by a threaded shaft 44 which engages a nut 45 mounted on the carriage. By means described or equivalent means, the torches are made to simultaneously traverse the line of weld in a relationship which is indicated in Figure 7.

Welding mechanism is described in the said copending application of Reed; and much of this mechanism may be employed in welding according to our present process. In fact, if desired, using a clamping arrangement such as shown in Figure 6, the welding head and associated parts of the said Reed application may be duplicated below the butted joint. It will thus be evident that portions of the welded joint may simultaneously be formed by different pairs of torches, thus increasing the speed of the operation; and it will further be evident that the various features of automatic control which characterize the apparatus of the said Reed application may be applied to the apparatus herein described.

After the welding operation, the strip may be carried away from the welding head as shown in Figure 1 by pinch rolls 46 driven by motor 41. The line of weld may thus be positioned in a rolling device 45 so as to roll the weld. This device will preferably be the device which has been illustrated and described in the applications referred to above. For forming a coil of the strip, it is first turned as at 49 from the horizontal to the vertical position and is coiled on a vertical mandrel 50 driven by a motor 5|. The mandrel for a flange 52 on which the coil rests as set forth in the co-pending application of Asbury and Reed, Serial No. 132,826, filed March 24, 1937. The tight coiling of silicon steel strip or the like, not characterized by flatness, may be accomplished by making one or more turns on the mandrel loosely and then tightening these turns before making other turns. Thus as an automatic adjunct to the coiling device, and driven by the same motor, we provide a retarding means comprising an anvil 53 over which the strip passes, and friction shoes 54 which press the strip against the anvil. The friction shoes are operated by a cam arrangement 55 driven by the motor 5| so that the strip is retarded automatically at the end of each turn of the mandrel 50, or at the end of each small number of turns, while the mandrel continues to rotate. In this way a satisfactorily tight coil can be formed.

Modification may be made in our invention without departing from the spirit of it.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process of-weldlng silicon steel sheets so as to form strips of indefinite length which comprises clamping the edges of said sheets under a certain force effective over a certain area and shearing the edges of said sheets perpendicularly, clamping the sheet edges in butted relationship by treating each sheet edge to the same said force effective over the said same area, and welding the butted edges of the sheets together by impinging neutral flames against the butted joints from each side thereof simultaneously while confining said flames substantially to the butted joint and while rapidly abstracting heat elsewhere from the sheets so as to confine oxidizing temperatures to those portions of the sheets on which said flames impinge.

2. In combination in apparatus for the purpose described, a shear having clamping means Ior sheet edges cap ble of exerting a certain force over a certain area, a welding device having a pair vof clamping means for butted sheet edges, said clamping means capable of exerting the same said force efiective over the same said area, a carriage, torches mounted on said carriage so as to impinge flames on the butted joint simultaneously and substantially oppositely from both sides, means for causing said torches to traverse the butted joints simultaneously, said clamping means so shaped as to confine the flames of said torches substantially. to said butted portions, and means for cooling said clamping .means to an extent sufficient to maintain the edges or said sheets below oxidation temperatures elsewhere than at thearea of said sheet edges on which said flames impinge.

E0 REED. 

